<!--
 * @Description: 
 * @Autor: ZachGmy
 * @Date: 2021-06-21 09:48:35
 * @LastEditors: ZachGmy
 * @LastEditTime: 2021-06-21 09:59:09
-->
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      width: 100px;
      height: 100px;
      /* 内边距 */
      padding: 20px;
      /* 外边距 */
      margin: 20px;
      /* 边框 */
      /* border: 宽度 样式 边框的颜色; */
      border: 5px solid blue;
      background-color: red;
      /* 设置盒子属性 */
      box-sizing: border-box;
    }
  </style>
</head>

<body>
  <div>hello</div>
</body>

</html>